Insecticide



Patented Dec. 21, 1937 UNITED STATES INSECTICIDE Howard A. Jones,Washington, D. 0., dedicated to the free use of the People of the UnitedStates of America No Drawing. Application July 3, 1937,

Serial No. 151,915

8 Claims. (01. 2c0 54) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) r This application is made underthe act of March 3, 1883, as amended by the act of April 30, 1928, andthe invention herein described, and claimed, if patented, may bemanufactured and 5 used by or for the Government of the United Statesfor governmental purposes without the payment to me of any royaltythereon.

I hereby dedicate the invention herein described to the free use of thePeople of the 10 United States of America to take effect on the grantingof a patent to me.

My invention relates to a heretofore unknown compound made from achemical combination of rotenone and dichloroacetic acid.

15 The object of my invention is to produce this new compound which hasvaluable properties as an insecticide, and is of considerable importancein the development of new and shortened methods for the analysis ofmaterials containing rotenone.

My invention is a new chemical compound and contains 75.35 per cent byweight of rotenone and 24.65 per cent by weight of dichloroacetic acid.The empirical formula of this new com- 5 pound is thereforeC23H220aC2I-I202CI2. This new compound would be classified in the art asan addition compound, and may also be referred to as a solvate. This newcompound differs markedly from all other known addition com- 30 pounds,or solvates, of rotenone in that it is a compound of rotenone and astrong, or highly ionized, acid.

I have prepared this new chemical compound and have found that itpossesses distinctly different physical and chemical properties fromthose of both rotenone and dichloroacetic acid. The compoundcrystallizes in colorless, lath-like crystals,- while rotenonecrystalizes in flat, hexagonal-shaped plates. This compound also dif- 40fers chemically from rotenone in that it possesses an acidic group whichmay be titrated with alkali by dissolving the compound in awaterimmiscible solvent such as chloroform and shaking this solutionwith water while adding 45 the alkali. Because of this fact the compoundis useful in the development of shorter analytical procedures for thedetermination of rotenone. Rotenone itself does not possess any suchacidic group and cannot be titrated with alkali in this 50 way.

The inventor has already reported in the literature an addition compoundof rotenone and acetic acid in which the molecular ratio is two mols ofrotenone to one of acetic acid. I have 55 also found that other fattyacids and chlorinated fatty acids combine with rotenone in this mol.ratio. Thus propionic acid and alpha-chloropropionic acid form compoundsin which the molecular ratio is two mols of rotenone to one of acid.However, the present compound of ro- 5 tenone and dichloroacetic acid isentire-1y different from these in the fact-that it is the only one whichhas thus far been found in which rotenone combines With an acid in amoi. ratio of one to one. This is particularly advantageous in theapplication of this compound to use in analytical procedures in that amuch larger titer of alkali is obtained than with other compounds inwhich rotenone combines with acids,

and the resulting methods are correspondingly more accurate. The factthat dichloroacetic acid is far superior to other fatty acids andchlorinated fatty acids in solvent power for V rotenone is particularlyimportant from the standpoint of ease of preparation of the newcompound.

Furthermore the fusion of rotenone and dichloroacetic acid has resultedin a product possessing insecticidal properties different from thosepossessed by rotenone acting alone, and dichlog5 roacetic acid actingalone.

The compound of my invention may be prepared in several ways. It may beproduced from rotenone by dissolving said rotenone in dichloroaceticacid, heating the solution and adding water to obtain a crystallineproduct therefrom, said product being my invention.

This addition compound of rotenone and dichloroacetic acid is alsoproduced from extracts of the roots of plants of the genus Derrz'sdeguelia, extracts of the roots of plants of the genus Lonchocarpus,extracts of the roots of plants of the genus Tephrosia 'cracca, or fromextracts of any other plant material containing rotenone. This isaccomplished by dissolving any 40 of the above mentioned extracts indichloroacetic acid, heating the solution, adding a. suitable quantityof hot water and allowing the whole to cool. The material whichcrystallizes out is substantially the product covered by my invention.The preferred method for the purification of the product thus obtainedis to dissolve it in hot dichloroacetic acid, add a suitable quantity ofhot water, allow the whole to cool, and separate the material, whichcrystallizes out, by filtration or other similar means employed toseparate substances.

The methods of producing my compound are illustrated by the followingexamples:

Example I.2 grams of rotenone is dissolved in a mixture of 20 cc. ofdlchloroacetic acid and 5 cc. of water. The solution is warmed to atemperature of 50 C. and 150 cc. of water at the same temperature addedslowly with continuous stirring, when crystallization occurs. This mixture is cooled to 20 C. and'the crystalli'n'e compound filtered off andwashed with water at 20 C. until all excess dichloroacetic acid isremoved.

The crystalline product is dried to constantweight in a current of airat 40 C. The product so obtained is the pure addition compound ofrotenone and dichloroacetic acid, which is the product covered by thisinvention.

Example II grams of the extract from the roots of Derris deguelia sp. isdissolved in a mix"- ture of 25 cc. of dichloroacetic acid and 5 cc. ofwater. The solution is heated to a temperature ofe50 C. and '70 cc. ofwater at the same temperature added slowly with continuous stirring;This mixture is cooled to C. and the separated material filtered off,washed with water at 20 C. until all excess dichloroacetic acid isremoved, and dried'to constant Weight at 40 C. The product so obtainedis substantially the addition compound'of rotenone and dichloroacetic 2.A new chemical combination ,of rotenone and dichloroacetic acid havingthe empirical formula C23H220e.C2H202C12.

3. A process formaking a chemical compound of" rotenone anddichloroacetic acid, which comprises essentially dissolving" rot'endri'eiri' dichloroacetic acid, adding water and Separating the resultingcrystalline product.

41 A process for making a chemical compound of rotenone anddichloroacetic acid, which comprises essentially dissolving an extractof the roots of plants of the genus Derris deguelia, in dichloroaceticacid, adding water and separating the resulting crystalline product.

5; A -process for making a chemical compound of rotenone anddichloroacetic acid, which comprises essentially dissolving an extractof the rootsofplants of the genus Lonchocarpus in dichloroacetic'acid,adding water and separating the resulting crystalline product.

6. A process for making a chemical compound of rotenoneanddichloroacetic acid, which comprises essentially dissolving anextract of the roots ofplants of the genus Tcphrosz'a cracca indichloroacetic acid, adding'water and separatin 1 the resultingcrystalline product; 7; A-processyfor makinga chemical compound ofrotenone'and dichloroaceticaizid; which com-

